The present invention relates to aqueous compositions useful for adhering elastomers to other substrates.
It is often desirable to bond elastomers to other materials by using adhesive compositions. Substances that are bonded to each other with one or more adhesive compositions are herein referred to as “substrates.” Elastomeric materials may be desirably bonded to a variety of other materials (herein referred to as “second substrate”), including for example other elastomers, fabrics, plastics, engineering plastics, and metals.
An aqueous composition that has been used for adhering elastomers to metal involves the use of halogenated polyolefin polymer, aromatic nitroso compound, and phenolic resole, as disclosed in Mowrey, WO 9902583. Also, Kelley et. al. in U.S. Pat. No. 6,287,411 disclose the possibility of adding halogenated polyolefin, nitroso compound, and other additives to an aqueous adhesive that contains polyvinyl alcohol stabilized butadiene polymer latex formed by emulsion polymerization and that contains a so-called “methylene donor compound”.
Many compositions that are useful in adhering or bonding elastomers are available dissolved in organic solvents. However, it is desirable to provide such compositions in aqueous form, to avoid the hazards and environmental effects of organic solvents as well as to improve manufacturing and applications processes. Generally, polymers that are useful as part of compositions useful in adhering elastomers are provided in aqueous form by some type of suspension or emulsification that requires the presence of surfactant to provide stability. It is believed that the surfactant remains in the composition upon drying. Thus, when the adhesive bond is put to use, the affinity of surfactants for water makes the adhesive composition tend to absorb water from its environment and thus lose some of its effectiveness as an adhesive.
The problem addressed by this invention is the provision of aqueous compositions that bond elastomers in such a way that the bonds formed have good strength when exposed to water.